Relationship between dead wood as ant nesting material and coniferous forest use by Japanese black bears in summer

Japanese black bears (Ursus thibetanus) use coniferous forests in the summer, but details of their behavior remain unclear. Ants use dead wood as a nesting material, and a strong association is believed to exist between the distribution of ants and the use of ants by Japanese black bears in coniferous forests areas with dead wood. To clarify that relation, we tracked two Japanese black bears using a newly developed telemetry system (GPS-TX) for 13 days and 6 days in June-August 2012. We also examined the distribution of dying wood in forests. Results show that Japanese black bears used coniferous forest areas in summer frequently and ate ants that nested in dead wood there. Furthermore, coniferous planted forests included numerous areas with dead wood. Japanese black bears often used such areas as wood decay progressed. Conifer plantation forests are therefore important contributing factors to the supply of ants. Furthermore, our results suggest that forest practices in planted coniferous forests strongly influence the food resources of Japanese black bears in summer.